The internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the internet of things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The internet of everything (IoE), which is a combination of the IoT technology and the big data processing technology through connection with a cloud server, has emerged.
As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “security technology” have been demanded for IoT implementation, a sensor network, a machine-to-machine (M2M) communication, machine type communication (MTC), and so forth have been recently researched.
Such an IoT environment may provide intelligent Internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing information technology (IT) and various industrial applications.
A cloud storage service is a service in which a user device may have a storage of the user device at an internet. In the cloud storage service, the user device may access a cloud storage server in an environment in which an internet is possible to download a file of the user device which is stored at the cloud storage server, to upload the file of the user device to the cloud storage server, or to use a file stored at the cloud storage server (for example, streaming, editing, and/or the like).
Recently, various cloud storage services have been proposed, and typical examples are Dropbox©, One Drive©, Google Photos©, Amazon Photos©, N Drive©, and the like.
Recently, various cloud storage services have been activated. Specially, a major service provider such as Google Photos©, Amazon Photos©, and the like provides aggressively a cloud storage service. For example, Google Photos© provides a unlimited storage for storing pictures, and Amazon Photos© provides a unlimited storage for storing pictures to prime members.
Meanwhile, technical barriers to a cloud storage service become low, so many start-up companies which provide a cloud storage service have been founded. Specially, Amazon web services (AWS)© provided by Amazon© provides an infrastructure and a framework for which implementation and an operation may be relatively easy. Specially, in a case that AWS© is used, users which have less experience for implementing and operating a server may be relatively easy to implement and operate a server. So, many start-up companies have provided various services which use a cloud storage service.
A cloud storage service is actively applied to various environments. However, it is difficult for a user device to trust a cloud storage service provider, so the user device needs to encrypt data, e.g., a file sensitive to security in advance and upload the encrypted file to a cloud storage server.
In a case that a user device encrypts data to upload the encrypted data to a cloud storage server, the cloud storage server may not access the encrypted data uploaded by the user device without using a secret key of the user device. So, security for data is surely guaranteed, but it is impossible to use existing search processes.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.